Process of separating substantially pure fecl2 from material containing fecl2 and metallic cobalt



Patented May 4, 1954 rnoonss: F SEPAILATING SUBSTANTIALLY roan neonFROM-MATERIAL oon rammo swam-n. METALLIC comm Mar onflme tfi eham, i andwardlfieidler, Columbus, ohio, assignors, by mesne assignments, toBepublichSte'el Corporation,

le a d; o, a p ation f New Jersey No Drawin dlml N ovem er- 9, i95

erial No. 321,514

4 Claims, 1

T e p esent i ve tion rela s. to, a p o es fo h s ar o o ten-ousl ride rm ma r a cont ning m t lici cba t ne mbo men o this inv ntion-i as. a.par icu ar s e i lar Q e al -pro ess o trea ing re con ai in an and.cobalt valueslto obtain these values-sepaat y in some us u m- .Thepresent. applicati is e acre-u of seven ac-pending. applications all theinventions of t sam nv ntorsltio rq t es ase el tns to. ni k land rections inv l in n ck l. and t e, ot e thtc rdatinsm coba t andreactionsinvolving cobalt.v The cases. may be compared and di ingui hed as f llos S r- .-.i60 2. fi .ed:May 8, .9 r t sto treating a starting materialinihfi nQ i-eiaseous l d an 115 1. 5. ,f-Orm a on isti e s tially ofNiCl ndEeglz, and wherein there is m r F 91 aiiNiCla Th s st ne ater ais eate a r action or snbl matio fzo e. in th pr senc vi a erta n amuniq meta li r n o p odu e a fi l-product wh h is va or d e iZ, o ed fom he subl mat on one a su h, in v on y metal on a d meta li i e in thesublimationzone.

b. .ser. No. 210,433, filed February 10 1951. e a es o treatinaa s artng. m teri ssen ia y h same. as r- No.-. 0,8. p t in-ihis nstance thstart ng material nt duced intothe. r actionzone n a sclelye secuss atThe eac io an th final pr ucts are sub tant l y e me in S r, o, 0,821-

c,- Se I -1.160.822, fil ilM v .8, 59,.re1a es to e preventing orirninim z ne i a-nos ible back reaction. The starting materialconsistsessene ii v r ous chloride nd metall c n ck is d si to separateth se ateria Wi ut p r ttinaor at least mini izin a pos b eb eactionthereb tw e whi wo rodu ick l c ride an me allic-iron.- do t i the tar nateri lis nt o u int a r action or b i ation one. i whic metall c i onspre e t. The Startin mate a a in roduc din i on is in a o .aseou s te.The fina produc s a e .subs an al y pur ierro chlor de vapor, w ch. isremoved it m m sons as such, d m a iic' nick l and me allic: iron whichr main in thezone.

a process fortreating a starting materia'l sub- I stantiallythe same asin Ser. No. 169,821. This case has' been amended so as to preclude theclaims reading uponseparation of the products of the reaction byvaporizationas in Ser; No.

160,821.; clout thiscase theseparation following. the. rea tion is.eifested; by: withdrawing; the;-

tallio nickel produced (bya. reaction the same. as in Ser. No. 160,821)by withdrawing massive pieces-of iron, to which the: deposited nickeladheres physically, from the fused bath of the startingmaterials.Neither the. ferrous chloride nor any nickelonloride present isintentionally volatilized. Thisapplication is junior to application Ser.No. 160,821, so that. the. only subject matter clainiable therein issubject matter which cannotbe supported by the disclosure oi Ser, No.180,821; all the-common subject matter being claimed in Ser. No.160,821.

6. Ser. NO. 2Ei1,816, filed June 4, .1952 is the.

first of the three. cobalt applications and is the cobalt counterpartofthe nickelcase, Ser. No. 160,821, distinguishing therefrom byubeingdirected to cobalt and its chloridarather than nickel and itsrespective. chloride. This case. is furtherv distinguished in thewdegreeof purity of thesublimate.

fVSer. N0.-320,335, filed November 15, 1952,.is the cobalt counterpartvofinickel case, Ser. No. 210,433. It distinguishes from cobalt case Ser.No. 291,816- in thesame Way. discussed above as to the respectivelycorresponding nickel cases, While distinguishing from ,its correspondingnickel case, Ser. No. 210,433, by the differences between cobaltiandnickel.

g. Ser.- No. 321,514,.filed November 19,1952 (the present application),is the cobalt case corresponding to the nickel case .Ser. No. 160,822.-It distinguishes from the other cobaltcases asdiscussed above inrespect to the respectively correspondingnickei cases, whiledistinguishing from its .nickel:.counterpart, Ser. No. 160,822, by the(inferencesbetweenv nickel. and cobalt.

One of the-early phases of an overall process in which the presentinvention could serve as a particular step, could, for example, be thechloridizingoofthat part of an original iron-nickel- 'cobal-t orematerial from-Which the nickel values had been removed, asaby aselectiveprecipitation step; If such a chlor-id-izing-step, which forms no partof the present invention, be carried out underpconditions such thattheiron: values are selectively chloridized, while the. cobalt values arereduced to metalliccobalathere would be producedaa material containingFeClz,--metal1ic cobalt,,usually in finely divided form, gangue andpossib1y,-.in addition, somereduced metallic iron.

- Itissuch a mixture that is. contemplated as the star-ting'material forthe process of the present invention. It will be understood, of-course,that such a: material may ,be the result of other-procasses and thatthemethodofproducing the aforesaidmixtnre forms no partof thisinvention.

It is known that ferrous chloride can be vaporized and thereby separatedfrom inert materials under suitable temperature conditions. However, wehave found that when metalli cobalt is present, mixed with ferrouschloride, a bacl: reaction tends to take place between some of themetallic cobalt and the ferrous chloride present to form metallic ironand cobalt chloride. lihis reaction may be represented by the equation:

As will be more particularly pointed out in the specific exampleshereinafter given, the tendency of this reaction to proceed from left toright is more pronounced, the higher the ratio of FeClz to metalliccobalt. it will be seen that the occurrence of such reaction isundesirable for several reasons: first, the subllmed material will notconsist of substantially pure ferrous chloride as desired, but will becontaminated with cobalt chloride; and, second, at least some of thecobalt, which may be desired to be recovered in the metailic state, isconverted to a volatile chloride and lost or mixed with the ferrouschloride.

is general object of the present invention is, therefore, to provide amethod of separating ferrous chloride from the remaining materials inthe form of substantially pure ferrous chloride, containing not overabout 1% by weight of cobalt chloride and preferably substantially less,as an impurity.

it is a further object to maintain the metallic cobalt in the startingmaterial in metallic form, while minimizing the amount that will be lostas volatile cobalt chloride.

Summarizing the present invention, the separation of ferrous chloridecontaining less than about 1% cobalt chloride by weight as impurity isaccomplished by providing in the starting material an amount of metalliciron at least equal to the weight of the metallic cobalt therein. Themetallic iron may be all or in part present in the original mixture, orit may be entirely added. The term providing metallic iron or equivalentlanguage, as used in the claims, includes either a starting materialwhich has such metallic iron present initially, or a starting materialwhich had no, or too little, initial content of metallic iron, but towhich metallic iron has been added to the extent necessary, inaccordance with the present invention. Ihe material, which now includesferrous chloride, metallic cobalt, metallic iron and possibly some inertor gangue materials, is then heated to a temperature in the range ofabout 6t0 C. to about the boiling point of F6012 at the prevailingpressure for a time sufficient to vaporize the FeClZ present. FeClz.boils at about 1025 C. at 760 mm. pressure. Vaporized FeClz may, ifdesired, be removed from the non-volatile material by a sweep gas. As ithas been found that the equation given above, as illustrating a reactionwhich is to be inhibited or at least minimized in accordance with thepresent invention, is a reversible one which tends to reach anintermediate equilibrium condition, the present invention providesconditions assuring the desired results. Thus, by providing a quantityof fin ly divided iron in the material as aforesaid, there is assuredeither of the following results: (a) that the equation will operate inthe direction shown only to a very limited extent and will produce onlya small amount of CoClz, or, (b) sub stantially all of such CoCl2 as maybe formed will immediately react with metallic iron, present as.

aforesaid, to produce metallic cobalt and FeClz. The net result is thatby far the greater part of the metallic cobalt initially-present remainsas such in the non-volatile residue after all the FeClz initiallypresent has been sublimed or dis tilled therefrom.

Thus, in accordance with the present invention, it is necessary to havepresent metallic iron to react with any cobalt chloride which may beformed from a reaction between the metallic cobalt and the ferrouschloride originally present. We have found that when using an amount ofiron at least equal to the weight of the metallic cobalt present, theamount of cobalt chloride which is formed and carried over to thesublimate is reduced to such an extent that the ferrous chloride in thesublimate contains less than 1% by weight of cobalt chloride as animpurity. We have further found that if the iron is present in a ratioof about five parts by weight to about one part by weight of metalliccobalt, the sublimate obtained from heating such a material to atemperature where FeClz has a substantialy vapor pressure, will be FeClZcontaining less than about 0.2% COClz as an impurity. It is ourconclusion that when a 5:1 ratio of iron to cobalt is used, suchsublimate is for all practical purposes, substantially free of cobaltchloride. However, sublimates containing even smaller amounts of cobaltchloride as an impurity, may be obtained by the use of an amount of ironin excess of the amount needed to produce a 5:1 by weight ratio inrespect to cobalt, as set forth in detail in the specific examples whichfollow. Such conditions are undesirable only to the extent that theyreduce the purity of the metallic cobalt left as a residue after theFBClz has been removed.

As has been indicated above, the metallic iron which serves to inhibitas to minimize the formation and/or separation by sublimation from themass of volatile cobalt chloride and thereby serves to minimize the lossof cobalt in volatile form, may be initially present in the material insufficient quantity to produce this effect, or it may be Wholly orpartially added.

In View of the fact that a chemical reaction, involving the metalliciron, may be called for, in accordance with the present invention, asaforesaid, it is desired to have the iron present in a readily availableform. For this reason the iron is preferably present and/or isintroduced in a finely divided form and is well mixed with the othersolid and/ or liquid ingredients of the starting materials.

While we have found that the tendency of the reaction between ferrouschloride and metallic cobalt to form cobalt chloride and metallic ironis more pronounced as the ratio of ferrous chloride to metallic cobaltin the starting material increases, the purity of the sublimate withrespect to the amount of cobalt chloride contained therein as animpurity, can be controlled by the addition of metallic iron to anextent that is substantially independent of the ratio of FeClz tometallic cobalt in the starting material. This is amply demonstrated byactual examples of the rangemay be conveniently placed at about 600-acme-c7 C, at which: temperature EeCls has: a: substantial vaporpressure. Ithas been-found, in practice, thatattemperatures:-below-sabout 600? C., the rate of vaporizationof-"Feclz isso slow as-to make the process impractical. The upper limit of thetemperature range is fixe'd by the boilingpoint of ferrous chloride,which,=at standard-atmospheric pressure, is about -1025 C;In-:-view=of-the'fact that the volatilization .ofthe-ferrous chloride isendothermic process; thesrtemperature of the mass from which the FeClz'is volatilized-cannot' exceed this boiling point as -long; as any"substantial amount of ferrous chloride remains therein. However, it willbe understood that-in cases where the materialsare maintained: at 1superatmospheric pressures, the: boiling point of "fer-- rous chloride:will be -lii'gher, so that correspondingly higher temperature limitscanbe employed. Therefore, the Y, upper "limit f the temperature rangemay be the boiling point of ferrous chloride at whatever pressureisbeing employed.

In general, it may;be-said that while the tem perature is notparticularly critical, the rate of removal of the ferrous chloride fromthematerial present-is,,of'collrse, ajfunctionjoffthe temeratureso thatthe processiscompletely operative throughout a large temperature rangeas stated, the rate differing with different temperatures. The removalofvaporizedferrous chloride from the systemlmay'beieffectedeitherrby-operating at the a boiling. -point,-.of ferrous chloride or byusing a sweep gas ina-manner similar to a steam distillation. Such a:sweep gas is preferably an inertgas ;1suchas nitrogen.

It is contemplated that the process-ft the present invention may becarried on either as a batch or as a continuous type operation, suitableor conventional apparatus, per se forming no part of the presentinvention, being used in either case. The FeClz vapor, which is producedas a result of this process, may be condensed to solid or liquid form byany suitable means and may be used for any desired purpose.Alternatively, the vapor may be maintained at its high temperature andused for any purpose to which FeClz vapor is adapted. The residualmaterial will contain metallic iron and metallic cobalt. These metalsmay be separated from the gangue by any suitable method, magnetic orotherwise, and/or melted together to form an alloy.

The following examples illustrate the present process:

EXAMPLE I Table I Percent of Cobalt Chloride Weight Ratio of FerrousChloride Metallic Cobalt i gs g gfig fg' to Metallic Cobalt Converted toSubhmate in Volatile C0012 percent chloride-and metallic-cobaltisxconvertedto -volatile. cobalt chloride. It; will be further seen thatgreater: percentagesz of metallic cobalt are solconverted- :in::mixtures izwhere :the 'ratio of .ii errous:

chloride, to:metallic :cobalt 'isxhigh .thanlin' which thisxratios isrelatively low.

' A II The; effectrof. the-:additionnof; varyinglamounts' of metalliciron.omthezpurityaofthezferrous ch10 ride; obtainedrandxhe; percentzofcobalt-iconverted to ,thechloride isnillustrated by :the results set.

this table "were. obtained :by it-reating -mixtures:

containin :ferroustichlorideandimetalli'c cobalt, inpall-instances-zinthe weight :ratio of? 8.8.parts=:of

ferrous chloride to :1.:part.-' ofrmetallic. cobalt; at.

l00i) for about. one" hour in: a {stream :of;.nitrol TableeII CobaltChloride Percent of Me- Ratio. of Mailman-0n.- addedito mum Cobalt ggg-ff Metallic Cobalt converted to g g Volatile C0 C12 intpercent Thus itseen that as greateryamounts of metal.- lic iron are provided, thepurity of the ferrous chloride sublimate may be increased, although ithas not been found possible to eliminate entirely the presence of cobaltchloride as an impurity in the sublimate.

EXAlVIPLE III The results set forth in Table III below illustrate thatthe purity of the ferrous chloride sublimate can be controlled as to itscontent of cobalt chloride by the addition of varying amounts ofmetallic iron; and that this purity is controlled by the ratio ofmetallic iron provided to metallic cobalt originally present in themixture, rather than by the ratio of ferrous chloride to metallic cobaltoriginally present. The results set forth in this series of tests wereobtained by treating a mixture consisting of ferrous chloride andmetallic cobalt, always in the weight ratio of 8.8 parts of ferrouschloride per part of metallic cobalt, at 1000 C. in a current ofnitrogen for about one hour.

Table III Percent of Cobalt Chloride ride Sublimatc Volatile 000 2 inperce Ratio of Metallic Iron added to Metallic Cobalt This example,taken in conjunction with Example II above, illustrates that ferrouschloride con taining less than 1% of cobalt chloride as an impurity, maybe obtained by providing in the starting material an amount of metalliciron at least equal to the weight of the metallic cobalt therein, nomatter what ratio of ferrous chloride to metallic cobalt is originallypresent and also that a pure ferrous chloride product containing lessthan 0.2% COClz by weight may be obtained in all cases by providingsufiicient metallic iron to equal at least five times the weight of themetallic cobalt present in the starting material.

While it is desirable to obtain as pure a product as possible in termsof ferrous chloride, additions of large amounts of metallic iron willobviously result in the formation of a non-volatile residue which isprogressively less rich in metallic cobalt as the amount of metalliciron added is increased.

While we have described our process in general and have set forth insome detail the chemical and physical requirements thereof, it isrecognized that the process may be operated by the substitution of suchequivalents as will suggest themselves to those skilled in the art fromthe foregoing disclosure. We do not Wish to be limited, therefore,except by the scope of the appended claims, which are to be construedvalidly as broadly as the state of the art permits.

What is claimed is:

1. The process of separating ferrous chloride from a starting materialconsisting essentially of FC12 and metallic cobalt, while substantiallypreventing loss of cobalt in the form of CoClz, which comprisesintroducing said starting material in a non-gaseous state into asublimation zone, providing in contact with said material in saidsublimation zone sufficient metallic iron to assure that such iron ispresent in an amount at least equal to the weight of the metallic cobaltin said starting material which is in said zone, maintaining saidmaterial in said zone including said metallie iron within thetemperature range of about 600 C. up to the boiling point of FeClz atthe ambient pressure, vaporizing all the FeClz present, and separatingthe volatilized Feclz containing less than about 1% COClz by weight fromthe remainder of said material by passing the volatilized FeClz fromsaid zone to leave solely metallic iron and cobalt in said zone.

2. The process according to claim 1, in which said metallic iron ispresent in said zone in a weight ratio to metallic cobalt of at leastabout 5:1, the FBClz vapor so separated containing less than about 0.2%COClz by weight.

3. The process according to claim 1, in which said material includingsaid metallic iron is maintained at a temperature of about 1000 C.

4. The process in accordance with claim 1, in which said metallic ironin said reaction zone is in a finely divided condition, and in which thestep of removing said volatilized FeClz from said zone is assisted bypassing an inert gas through said zone to serve as a sweep gas.

References Cited in the file of this patent UNITED STATES PATENTS NameDate Kroll Mar. 19, 1946 OTHER REFERENCES Number Ljj.

1. THE PROCESS OF SEPARATING FERROUS CHLORIDE FROM A STARTING MATERIALCONSISTING ESSENTIALLY OF FECL2 AND METALLIC COBALT, WHILE SUBSTANTIALLYPREVENTING LOSS OF COBALT IN THE FORM OF COCL2, WHICH COMPRISESINTRODUCING SAID STARTING MATERIAL IN A NON-GASEOUS STATE INTO ASUBLIMATION ZONE, PROVIDING IN CONTACT WITH SAID MATERIAL IN SAIDSUBLIMATION ZONE SUFFICIENT METALLIC IRON TO ASSURE THAT SUCH IRON ISPRESENT IN AN AMOUNT AT LEAST EQUAL TO THE WEIGHT OF THE METALLIC COBALTIN SAID STARTING MATERIAL WHICH IS IN SAID ZONE, MAINTAINING SAIDMATERIAL IN SAID ZONE INCLUDING SAID METALLIC IRON WITHIN THETEMPERATURE RANGE OF ABOUT 600* C. UP TO THE BOILING POINT OF FECL2 ATTHE AMBIENT PRESSURE, VAPORIZING ALL THE FECL2 PRESENT, AND SEPARATINGTHE VOLATILIZED FECL2 CONTAINING LESS THAN ABOUT 1% COCL2 BY WEIGHT FROMTHE REMAINDER OF SAID MATERIAL BY PASSING THE VOLATILIZED FECL2 FROMSAID ZONE TO LEAVE SOLELY METALLIC IRON AND COBALT IN SAID ZONE.